Composition fob imbibition printing



Patented June 2, 19%

sii oFIcE BERTHA SUGDEN TUTTLE, OF BOSTON, MASSAGHUSETTS, ASSIGNOR T0TECHNIOOLOR MOTION PICTURE CORPORATION, 015 BOSTON, MASSACHUSETTS, A.CORPORATION OF MAINE No Drawing. Original application filed April 30,1926, Serial No. 105,861.

filed May 27, 1927.

This invention relates to the preparation of colored reproductions,especially upon transparent surfaces such as gelatine or the like, andto the resulting product.

In the art of preparing colored reproductions, especially uponabsorptive surfaces such as gelatinous films and coatings, it hasheretofore been proposed to print such surfaces from hardened films, ormatrices socalled, which bear the developed image or complementalportions of the image to hereproduced. This processdepends upon'theselective wetting of the developed areas of the matrix film (which mayalso stand in relief) by the dye solution and the non-wetting of theundeveloped areas. It also depends upon the direct transfer of the dyeas thus distributed to a relatively soft gelatinous surface,which takesplace upon efiecting intimate contact between the two surfaces,-byimbibition. Hence this general method of procedure is known in the artof color photography as an imbibition process.

In the practical application of this procedure even though the filmprinted is opaque and the reflected colors only are desired, it is founddifficult to secure and maintain accuracy of registry, relative colorvalues, definition, and like characteristics. When the reproductions aremade upon transparent materials, however, and are intended forprojection purposes as in cinema films, the relative depths andcontrasts of the several shadesand tones of coloration produced upon andin the surface (with respect to their several and composite lighttransmission values?l also become of primary importance. In sucinstances it is necessary that the coloring agents (usually dyes) shallnot only be proportionately and accurately distributed with respect totheir relative color Values and contrasts upon the matrix, but that theyshall also be quickly and accurately transferred and fixed to theprinted filmisurface.

It is further important that the relative contrasts or shades of a givencolor when thus transferred t p the printedfilm shall manifestthemselves with respect to transmitted light according to thecorresponding contrastspr degrees of development of the COMPOSITION FORIMBIBITION PRINTING- Divided and this application Serial No. 194,853.

several portion-s of the image upon the matrix film. When two or morecolors are to be used, it is essential that they be mutually inert inorder that their several and composite color values shall be maintainedand shall not be deleteriously affected or altered. Accordingly it is anobject of the present invention to provide a method for the preparationof colored reproductions, astypified by the more exacting application tocinema I films, whereby the conditions above set forth may be satisfiedanda product obtained of such qualities and characteristics as shallsuccessfully adapt it to its intended use. Other and more specificobjects of the invention will appear from the following disclosure.

It is found, as a part of the present invention, that whereas a matrixfilm may be developed to present degrees of density or contrastcorresponding to the complete range of the & DJ) scale, these gradationsmay not be reproduced by corresponding intensities or concentrations ofa dye solution adsorbedupon them, or, if such relative distribution ofdye is accomplished on the matrix, that it is not preserved andmaintained in the image which results upon" transferring the dye to thesecond relatively soft gelatine sur-- by the addition of albuminoriotheramphoteric colloid thereto, followed by the coagulation andremoval of the colloid, together with those components of the dye whichare susceptible to precipitation or selective segregationiupon contactwith a surface such as the gelatine matrix.

The dye solution so treated is more uni- .formly distributable over thedeveloped matrix surface and is adsorbed thereby more nearly inproportion to the relative contrasts or degrees of development which itpresents. Moreover, it is susceptible of being completely-transferredfrom the wet matrix to the soft, gelatine surface, by imbibition, andconsequently a wider range of color values and contrasts is madepossible in the printed image produced. 1 It is also found that thissurfaces as distinguished from those which are adsorbed by and adhere tothe free surface of the gelatine' only or are unequally penetrativethereof.

It is well recognized that in general acid dyes are more suitable thanbasic dyes, and

cable, however,

it has also been observed, Lemaire Brit. J our. Phot. 1911, 58, 969 andCurtis and Lemoult, Compt. Bend. 1905, that sulfonic acid dyes take moreactively upon gelatine, in proportion to the'number of sulfonic groupswhich they contain. Accordingly,*such dyes may be descriptivelydesignated as gelatine penetrative dyes, and While many of them may notbe suitable for the purpose of dyeing transparent films on account ofother and undesirable attributes, they may be considered, in the aspectof penetrability and resultant contrast effects upon gelatine surfaces,as fundamentally appropriate coloring agents.

It may here be remarked that in colored transparent films where thetransmitted light eflect obtained by'a given dye is due to itsabsorption of the remaining elements of the spectrum, it is essentiallydesirable that through an area of any given color, for example an areacontaining a single dye, the transmitted color shall be of thespecifically appropriate portion of the spectrum and that the absorptionof colors in other portions of the spectrum shall be complete, orsubstantially so, in this area. It is further desirsuch areas shall notbe reduced in intensity except in proportion to the contrast or shade ofthe transmitted color which is desired.

It is a characteristic of most dyes that when color contrasts are soughtto be obtained therewith corresponding to the deeper shades of thetransmitted colors, (for examge, optical density of 2.0 ormore on the &D. scale,) they are visually indistinguishable. This is probably due tototal light bsorption or reduction of light intensity in- -stead ofselective absorption of other spectral opaque formation.

colors only and the continued transmission of the color of the dye. Thismay also be caused by a concentration of the dye substance at or nearthe surface in a concentrated and resultingly solid and relatively Theshades of red, for depth of color correspondto the darkerzones of the H.& D. scale are by transmitted light indistinguishable in printed filmsheretofore made, and may appear black or may show an imperfect orrelatively lower light absorption in some other part of the spectrum,for example, blue, thus that the transmitted light in reo'neoe shiftingthe color quality of such light as is transmitted away from the red,giving purplish tones. Such a circumstance may arise, for example, inreproducing the image of a red curtain in which the folds actually 1present all gradations of red from a brilliant carmine to an effectiveor possibly a true black. In the reproduced print or image of such acolor range, as heretofore obtained the higher numbers or darker shades,as represented by proportionately greater densities of the dyesubstance, appear alike and substantially black.

Bv employing a dye which is characterized by fixation with the gelatinesubstance and by freedom from self-agglomerating components whichdeposit upon the surface, but which penetrates freely and preferably ata substantially uniform degree of dispersion or concentration throughoutthe depth or depths to which it reaches into the gelatine (therebyavoiding segregated layers of dye and also leaving the normaltransparency of the gelatine unimpaired) improved color contrast effectsare obtained by the present invention. It may be considered that by thusspacing the dye through an appreciable depth of the gelatine substance,substantially proportionate to the amount of dye imbibed in any unit ofa-rea, the intensity of light may be transmitted through the gela-tineand dye undiminished and also be reflected from one minute dye surfaceto another, thus passingthrough intermediate paths of relativelytransparent media. In this manner the transmitted light, which might besubstantially excluded by a relatively thin but compact layer of dye,-asmanifested more pan ticularly in the deeper shades and hence greaterthicknesses and/or concentrationsmay be permitted to pass relativelyfreely, by transmission and reflection, through a film in which the sameabsolute amount of dye substance is applied per unit of area but isdistributed'through an appreciable depth or thickness of the film wlthan intervening medium of transparent gelatine.

It is often found, however, exhibit a satisfactory degree of relativeabsorption towards matrices and proportionate netrabilities into thegelatine films to be printed therefrom (and hence make possible a widerange of contrasts, equal e. g. to the full H. & D. scale) tend also topresent diffused or indistinct margins,-in short poor definition. Thisis thought to be attributable to the very factor of ready penetrabilityor absorption or imbibition into the gelatine film,-but possibly also tolateral dispersion of the dye.

By the present invention, this difiiculty is overcome by employing inthe dye solution a viscosity agent capable of retarding dispersion ofthe solution, such as a second dye characterized by good definition andapprothat dyes which 7 eer/see priate color value,,without regard to (orpossiblyadvantageously of) low penetrability, Such addition ispreferably made in relatively small. proportions,-and introduces theeffect of arresting marginal creepthrough or upon the printed surfaceabove alluded to, may be attributed to a slight retardation of thenormal diffusion of the dye in the gelatine substance,which is moreespecially effective and more observable in the weaker or less activeareas of dispersion. extraneous of the areas directly printed byimbibition contact. By way of comparison, such retardation in thenormally liquid flow of the dye makes it resemble the flow of plasticsubstances, which is more restrictcd,and which ceases abruptly when theactivating force is removed or falls below a definite value. I

Briefly defined, the method of the invention includes wetting adeveloped matrix film, typically presenting in its developed areas, awide range of image contrasts (corresponding, e. g. to the full H. & D.scale) with a dye solution characterized. by mani festing selective andrelatively proportioned adsorption toward such developed areas of thematrix on the one hand, and, on the other, a rapid and uniformlypenetrative and distributive absorption into a relatively soft i. e.dye-absorptive) and preferably wet surface of a gelatine film (with orwithout qualifying agents as hereinafter set forth) and firmlycontacting the thus wet matrix surface with the softgelatine surface tobe printed, preferably underwater and for a short interval of timefollowed by separating the two surfaces,-and repeating the printingoperation thereo'n, if desired, with other printing matrices carryingimages, usually complemental to the first and with a dye or dyes ofcomplementary colors.

More specifically, the invention is directed to reproductions uponsurfaces of a gelatinous compositionsuch as those provided ontransparent celluloid films and the like by coating with a gelatinsolution. It is further desirable and, for purposes of highlysatisfactory cinema production, practically.

essential that the coloring agent or dye shall be of marked thoughrelatively uniform adsorption or penetration characteristics withrespect tothe gelatinous surface, without appreciable tendency todifiuse laterally either through or over the gelatine surface, uponcontacting therewith. A further desirable qualification of the dye isthat it shall promptly become and thereafter remain permanently fixed insitu, as by a more or less stable chemical or physical association, withthe gelatinous substance.

For example, the dye solution should not tend-to adhere to norbewithdrawn by the matrix surface, upon separation from the printedgelatine surface therefrom. And moreover it should attain its maximumdepth of penetration relatively promptly, leaving a uniform distributionof dye therethrough, without subsequent tendency to disperse through thefilm, nor leave any superficial liquid to disperse laterally between thecontacting surfaces.

The process of the invention will be described in its application forthe preparation of multi-colored reproductions on films for movingpictures and the like. For such purposes a cellulosic film, of celluloidor other transparent material, is first prepared, such as is generallyemployed for photographic use. To this is applied a coating of asolution containing gelatine, a hardening agent such as potassiumdichromate and usually an organic acid such as acetic acid. The coatingthus formed is then allowed to dry rapidly and is subsequently hardenedto the desired degree in known ways.

A plurality of matrix films, each bearing an image to correspond to one(or more) of the primary colors or to each of two (or more) complementalcolors appearing in the reproductlon to be made, 1s next prepared, as bysuitably exposing and developing or light printing and developing aphotographic film therefor. For example, where the complementary colorsred and green are to be provided, a film matrix may be prepared anddeveloped to correspond to the red portion of the images in the subjectto be reproduced and a second matrix film may be developed to correspondto the green portions thereof. This may be effected in any suitablemanner, according to the appropriate photographic technique, which hasbeen fully established for such purposes and is well known in the art.

For the purpose of making cinema reproductions, the matrix surface ismost convenout the range of the H. & D. scale. The dye is notpermanently absorbedby the matrix film, but may be transferred to asofter gelatine surface (as above defined) by contact. Hence, suchmatrices may be satisfactorily used for imbibition printing. However, itmay be desirable that the dye-wet or printing areas shall also stand inrelief above the nondyed portion of the matrix. To this end it is commonpractice to dissolve off the undeveloped areas of gelatine, which alsoremoves gelatine from the partially developed areas substantially inproportion to their respective degrees or amounts of non-developedcomponents. This leaves the image or images on the matrix surface,whichare already developed, according to the corresponding initial lightcontrasts in the original, and hence with respect to the relativecapacity of the surface to adsorb the dye solution, still furtherdeveloped by physical relief.

In the application of the invention to the preparation of colored filmsthese matrix images will be developed to represent the relativeintensities of a single primary or complementary color component of theoriginal or of the colored reproduction which is to be made. For thispurpose, where multicolored reproductions are to be made, the followingdyes have been found especially appropriate for producing complementaryreds and greens:

Definition red .1 7 oiacn u acetic acid 5.0% -4 Made up to 18,000 cc.with water.

grams 900 cc.

Green Wool green S, sodium salt of tetramethyldi-amino-dl-phenylB-hydroxy-naphthyl carhinol-disulfonic acid anhydride, color index 737(4.5% egg-treated) 6,000 cc. Metanll yellow, sodium salt of M-sulfo-hcn-Y zcne-azo-di-phenyl amine, color index 138 22 grams Glacial acetic acld600 cc.

Made up to 18,000 cc. with water.

The egg treament, mentioned above and V referred to in the formulae,consists in the ad:

dition of the white of egg or a like amphoteric colloid to the dyesolution, followed by coagulation of the colloid as by boiling andremoval of the coagulated colloid, together with extraneous solids orsolid-forming constituents, from the solution.

The matrix film, bearing the images which are to be reproduced in red,is now immersed in the red dye solution, rinsed, and brought intofirmand intimate contactwith the gelatinized surface of the blank film(preferably images and under water to eliminate gaseous enclosures ofair) and a slight pressure is applied betweenthe contacting surfaces, asby passing between pressure rollers. Such contact is maintained'foranappreciable period of time, as determined by experiment to be sufficientfor complete transfer ofthe dye from the matrix to the blank film. Thefilms are then separated. The printed film is preferably dried, and nextbrought into contact 'with the matrix film bearing the images tobereproduced in green, which has been similarly wet by passing throughthe green dye solutiomand then rinsed. The two films are preferablybrought together under water as before and pressed firmly together.Thereupon the green dye is transferred from the matrix to thegelatinesurface and, by virtue of its complementary relationship thereto, formsa complete composite color reproduction on the gelatine film. Theprinted film is then dried in the usual manner and is ready for use.

In a printed film as thus produced it is found that the definition, i.e. accuracy of transfer in the narrow areas and margins of the severalimages and in the overlapped color areas, is greatly improved overprocedures heretofore known and practiced in the art. It it alsoobserved, upon passing light through the colored film and focusing thesame upon a white surface, that the transmitted light is of purer colorvalue than usually attained, manifestly a lower absorption of the colortransmitted and a higher absorption in other portions of the spectrum,throughout the ranges of density and concening through subst ntially theentire H. & D. scale, metanil yel w and fast red S. conc. also reducethe apparent tendency of other dyes to creep and disperse beyond theirmargins into the film surface, so that a marked improvement indefinition of the margins of overlapping of color zones is fected. c

It is to be understood that various moditration ordinarilyagncountered,and extendfications of procedure and substitutions of materials may bemade within the scope of the invention but that such modifications andsubstitutions are to be considered as comprehended by the abovedisclosure and included within the terms of the following claims.

I claim:

1. A composition for imbibition printing, comprising a liquidcharacterized by containing a dye substance in solution and by normallymanifesting a marked penetrability of the solid to be printed therewith,and a viscosity increasing agent, added thereto.

2. A fluid composition for imbibition printing, comprising a liquidcharacterized by containing a dye substance in solution and by normallymanifesting a marked penetrability memos of the surface to be printedtherewith and a second liquid characterized by manifesting lowpenetrability or dispersion into such surface, said liquids beinmut-uall miscible.

- 3. A fluid compositlon for im ibition printing comprising adyesolution, characterized by normally manifesting a markedpenetrability into a gelatinous surface, to depths proportional to theamount applied thereto and of uniform distribution throughout thepenetrated depth, and a viscosity agent uniformly miscible therewith andcharacterized by imparting plastic flow to the composition.

4. A liquid composition for imbibition printin of films comprising agelatine penetrative dye and a dye characterized by high /viscosity..

5. A dye soiution for use in imbibition printing, comprising a gelatinepenetrative dye characterized by manifesting uniformity V, metanilyellow (color index 138).

me at Boston, Massachusetts,

Signed by this 25th day of May, 1927. i

,. BERTHA SUGDEN TUTTLE.

